1. Field of the Invention:
[0001] The present invention relates to a sliding-vane rotary compressor suitable for use
in an automotive air conditioning system.
2. Related Art:
[0002] There are known two types of sliding-vane rotary compressors: one has dual operating
compartments as disclosed, for example, in Japanese Patent Laid-open Publication No.
60-204992, and the other has an eccentric rotor as shown, for example, in Japanese
Patent Laid-open Publication No. 61-89993.
[0003] The dual compartment type compressor, as shown here in FIG. 10 of the accompanying
drawings, includes a cylinder 1 having a substantially elliptical bore in which a
rotor 2 is rotatably disposed. The rotor 2 is slidingly engageable with the inner
wall of the cylinder 1 along a minor axis of the elliptical bore so as to define therebetween
two operating compartments 3a, 3b disposed in symmetric relation to one another. The
rotor 2 carries thereon a plurality (five being shown) of radially movable vanes 6a
- 6e slidably engageable with the inner wall of the cylinder 1. The cylinder 1, the
rotor 2 and the vanes 6a -6e define therebetween compression chambers 8a - 8e which
varies in volume with each revolution of the rotor 2. The cylinder 1 has two discharge
holes 22a, 22d which are opened and closed by corresponding discharge valves 29a,
29b. The cylinder 1 is surrounded by a shell 47 with a space leaving therebetween
for the passage of a discharge gas.
[0004] The eccentric rotor type compressor, as shown in FIG. 11, includes a cylinder 1 having
a circular bore in which a circular rotor 2 is disposed in eccentric relation to the
bore with a part of its periphral surface held in sliding contact with a portion of
the inner wall of the cylinder 1 so as to define therebetween a single operating compartment
3. The rotor 2 supports thereon a pair of substantially radially movable vanes 6a,
6b slidably engageable with the inner wall of the cylinder 1. The cylinder 1, the
rotor 2, and the vanes 6a, 6b jointly define therebetween two compression chambers
8a, 8b which vary in volume with each revolution of the rotor 2. The cylinder 1 has
at least one discharge hole 22 and a discharge valve 29 for opening and closing the
discharge hole 22. Unlike the dual compartment type compressor wherein the cylinder
1 is disposed in the shell for defining therebetween a discharge gas passage, the
eccentric rotor type compressor includes a cover 25 attached to the cylinder 1 to
cover the discharge valve 29 with a channel leaving between the cover 25 and the cylinder
1 for the passage of the discharge gas.
[0005] The dual compartment type compressor is advantageous in that the discharge gas passage
can be sealed reliably with utmost ease by means of the shell 47 extending around
the cylinder 1. The compressor having such shell 47 is however large in size and heavy
in weight. On the other hand, the eccentric rotor type compressor is compact in size
and light in weight because the cover 25 extends only in the vicinity of the discharge
valve. The compressor having such cover 25 is however defective in sealing as described
below in greater detail.
[0006] As shown in FIG. 12, the arcuate or dome-like cover 25 is disposed on the cylinder
1 in such a manner to connect the vicinity of the discharge valve 29 in fluid communication
with a discharge connecting hole 30 extending through a radial extension of a side
block 11 secured to a rear end of the cylinder 1. A pair of O-rings 48a, 48b are disposed
around the discharge valve 29 and the discharge connecting hole 30, respectively,
to provide two seal surfaces extending perpendicular to one another. The cover 25
is secured to the cylinder 1 by four screws 26a - 26d and also to the side block 11
by two screws 49a, 49b. With this arrangement, the O-ring 48a is elastically deformed
to lie flatwise over the cylinder 1 as the screws 26a - 26d are tightened. On the
other hand, the O-ring 48b is elastically deformed when the screws 49a, 49b are tightened.
Since the two O-rings 48a, 48b extend perpendicularly to one another, the cover 25
is likely to be displaced away from the cylinder 1 when the screws 49a, 49b are tightened
first. With this displacement of the cover 25, only an insufficient compression of
the O-ring 48a and hence an insufficient seal is obtained even when the screws 26a
- 26d are tightened thereafter. To avoid this difficulty, tightening of the screws
26a - 26d must be done first while continuously urging the cover 25 toward the side
block 11. Such assembling operation is however tedious and time-consuming and seals
thus provided are still unsatisfactory.
SUMMARY OF THE INVENTION
[0007] It is therefore an object of the present invention to provide a sliding-vane rotary
compressor which is compact in size and light in weight due to non-inclusion of a
shell.
[0008] Another object of the present invention is to provide a sliding-vane rotary compressor
having a hermetically sealed discharge valve portion.
[0009] A further object of the prsent invention is to provide a sliding-vane rotary compressor
having a discharge part which can be assembled easily and less costly.
[0010] A still further object of the present invention is to provide a sliding-vane rotary
compressor incorporating structural features which enable an adjustable control of
the displacement of the compressor according to operating conditions.
[0011] According to a first aspect of the present invention, there is provided a sliding-vane
rotary compressor comprising:
a cylinder and a rotor rotatably disposed in said cylinder so as to define therebetween
an operating compartment, the rotor carrying thereon a plurality of approximately
radially movable sliding vanes, there being defined between the cylinder, the rotor
and the vanes a plurality of compression chambers which vary in volume with each revolution
of the rotor;
a pair of side blocks secured to opposite ends of the cylinder;
a pair of heads secured to the side blocks, respectively, on opposite sides of
the cylinder;
one of the side block and one of the heads secured to the one side block jointly
defining therebetween a low pressure chamber extending in fluid communication with
an intake port of the compressor;
the other side block and the other head jointly defining therebetween a high pressure
chamber extending in fluid communication with a discharge port of the compressor;
the one side block having an intake hole connecting the low pressue chamber and
the operating compartment;
the cylinder having a recess defined in an outer surface thereof, and a discharge
hole having one end opening to the operating compartment and the other end opening
to said recess;
a cover secured to the cylinder and extending over the recess to close the latter,
there being defined between the cylinder and the cover a valve receiving chamber;
a discharge valve disposed in the valve receiving chamber for opening and closing
the discharge hole; and
the cylinder and the other side block having a discharge connecting hole extending
between the recess and the high pressure chamber.
[0012] As described above, the discharge connecting hole for connecting the interior space
of the recess and the high pressure chamber extends in the cylinder and said other
side block with the result that a seal between the cover and the side block is no
longer necessary.
[0013] According to a second aspect of the present invention, there is provided a sliding-vane
rotary compressor comprising:
a cylinder and a rotor rotatably disposed in said cylinder so as to define therebetween
an operating compartment, the rotor carrying thereon a plurality of approximately
radially movable sliding vanes, there being defined between the cylinder, the rotor
and the vanes a plurality of compression chambers which vary in volume with each revolution
of the rotor;
a pair of side blocks secured to opposite ends of the cylinder;
a pair of heads secured to the side blocks, respectively, on opposite sides of
the cylinder;
one of the side block and one of the heads secured to the one side block jointly
defining therebetween a low pressure chamber extending in fluid communication with
an intake port of the compressor;
the other side block and the other head jointly defining therebetween a high pressure
chamber extending in fluid communication with a discharge port of the compressor;
the one side block having an intake hole connecting the low pressue chamber and
the operating compartment;
the cylinder having a recess defined in an outer surface thereof, and a discharge
hole having one end opening to the operating compartment and the other end opening
to said recess;
a cover secured to the cylinder and extending over the recess to close the latter,
there being defined between the cylinder and the cover a valve receiving chamber;
a discharge valve disposed in the valve receiving chamber for opening and closing
the discharge hole;
the cylinder and the other side block having a discharge connecting hole extending
between the recess and the high pressure chamber; and
a displacement-adjustment mechanism incorporated in the one side block and the
one head for adjusting displacement of the compressor.
[0014] With this construction, a shell as required in the conventional compressor is no
longer necessary and hence the compressor of this invention is compact in size and
light in weight and is capable of adjusting the displacement thereof.
[0015] Many other advantages and features of the present invention will become manifest
to those versed in the art upon making reference to the detailed description and the
accompanying sheets of drawings in which preferred structural embodiments incorporating
the principles of the present invention are shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016]
FIG. 1 is a longitudinal cross-sectional view taken along line I - I of FIG. 2, showing
a sliding-vane rotary compressor according to a first embodiment of the present invention;
FIG. 2 is a cross-sectional view taken along line II - II of FIG. 1;
FIG. 3 is a side view of a first side block of the compressor;
FIG. 4 is an exploded perspective view, showing a discharge valve and its related
parts of the compressor;
FIG. 5 is a longitudinal cross-sectional view showing a part of a compressor according
to a second embodiment;
FIG. 6 is a longitudinal cross-sectional view of a sliding-vane rotary compressor
according to a third embodiment;
FIG. 7 is a cross-sectional view taken along line VII - VII of FIG. 6;
FIG. 8 is a cross-sectional view taken along line VIII - VIII of FIG. 6;
FIG. 9 is a perspective view of an adjustment member of the compressor shown in FIG.
6;
FIG. 10 is a cross-sectional view of a conventional dual-compartment type sliding-vane
rotary compressor;
FIG. 11 is a cross-sectional view of a conventional eccentric-rotor type sliding-vane
rotary compressor; and
FIG. 12 is an exploded perspective view showing a discharge valve and its related
parts of the compressor shown in FIG. 11.
DETAILED DESCRIPTION
[0017] As shown in FIGS. 1 through 4, a sliding-vane rotary compressor embodying the present
invention includes a cylinder 1 and a rotor 2 rotatably disposed in a substantially
elliptical bore in the cylinder 1. The rotor 2 is sealingly engageable with the inner
wall of the cylinder 1 along a minor axis of the elliptical bore so that the there
are defined between the rotor 2 and the cylinder 1 two operating compartments 3a,
3b disposed in symmetric relation to one another. The rotor 2 is fixedly mounted on
a drive shaft 4 in concentric relation thereto and includes a plurality (five in the
illustrated embodiment) of approximately radial slots 5a - 5e in which vanes 6a -
6e are slidably inserted, respectively.
[0018] A pair of front and rear side blocks 7a, 7b is secured to opposite ends of the cylinder
1 and held in sliding contact with the rotor 2 and the vanes 6a - 6e. Thus, there
are five compression chambers 8 defined between the cylinder 1, the rotor 2, the vanes
6a - 6e and the side blocks 7a, 7b. The drive shaft 4 is rotatably supported by the
side blocks 7a, 7b via a pair of radial bearings 9a, 9b. The front side block 7a has
a pair of internal lubricant supply grooves 10a, 10b extending in a V-shaped fashion
for the passage therethrough of a lubricating oil flowing from a lower portion of
a front head (described later) to the interface between the rotor 2 and the front
side block 7a and also to the back of each vane 6a - 6e.
[0019] A pair of generally cup-shaped front and rear heads 9a, 9b is secured to the front
and rear side blocks 7a, 7b, respectively, on opposite sides of the cylinder 1. The
front head 11a includes a hollow cylindrical hub 12 projecting axially outwardly away
from the front side block 7a for receiving therein an electromagnetic clutch (not
shown). The drive shaft 4 has an end portion extending longitudinally in the hub 12
for being releasably coupled with an engine crankshaft (not shown) via the clutch
to receive the engine torque. A mechanical seal 13 is disposed between the end portion
of the drive shaft 4 and the front head 11a.
[0020] The cylinder 1, the side blocks 7a, 7b and the heads 11a, 11b have respective flat
confronting end surfaces engageable flatwise with each other to provide a hermetic
seal with or without a separate sealing means disposed therebetween. In the illustrated
embodiment, a pair of first and second O-rings 14a, 14b is interposed respectively
between the front side block 7a and the cylinder 1 and between the cylinder 1 and
the rear side block 7b. The rear head 11b has defined therein an intake port 15 and
the front head 11a has defined therein a discharge port 16. The intake port 15 is
connected in fluid communication with a low pressure chamber 17 defined between the
rear side block 7b and the rear head 11b. The discharge port 16 is connected in fluid
communication with a high pressure chamber 18 defined between the front side block
7a and the front head 11a. The front side block 7a and the front head 11a also define
therebetween a low pressure guide chamber 19 opening toward the mechanical seal 13.
The low pressure guide chamber 19 is held in fluid communication with the low pressure
chamber 17 through a low pressure guide groove 20 extending in the drive shaft 4.
With this arrangement, a low pressure introduced in the low pressure guide chamber
19 lowers the loads on the mechanical seal 13, thereby enabling the mechanical seal
13 to operate reliably for a prolonged period of time.
[0021] The rear side block 7b has a pair of intake holes 21a, 21b defined therein in symmetric
relation and connecting the low pressure chamber 17 with the operating compartments
3a, 3b. With the intake holes 21a, 21b thus arranged, the low pressure chamber 17
is brought into fluid communication with the compression chambers 8a - 8e when the
respective compression chambers 8a - 8e increase in volume. The cylinder 1 has two
sets (only one set being shown) of discharge holes 22a - 22c extending radially across
the peripheral wall of the cylinder 1. The discharge holes 22a - 22c have their one
ends opening to the operating compartments 3a, 3b at diametrically opposite portions
of the inner wall of the cylinder 1 which extend along the minor axis of the elliptical
bore. The outer periphral surface of the cylinder 1 is flatted at two diametrically
opposite portions thereof for the attachment of a pair of arcuate covers 25a, 25b.
Each of the flatted cover attachment portions 23a (only one shown) includes a recess
24a having three laterally spaced arcuate grooves to which the other ends of the respective
discharge holes 22a - 22c are open.
[0022] Each of the covers 25a, 26b is secured to the cover attachment portion 23a by means
of four screws 26a, 26c, 26d; 26e, 26f (five being shown) threading through the cover
25a, 25b into the cylinder 1. Disposed between the covers 25a, 25b and the cover attachment
portion 23a is a third O-ring 14c extending around the recess 24a to provide a hermetic
seal. The covers 25a, 25b has a recessed arcuate inner wall so that there is defined
between the covers 25a, 25b and the recess 24a in the cylinder a valve-receiving chamber
27a. The cover 25a, 25b also includes three (only two being shown) laterally spaced
stopper projections 28a, 28b extending toward the cylinder 1 in alignment with the
respective discharge holes 22a - 22e.
[0023] The valve-receiving chambers 27a receive respectively therein a pair of discharge
valves 29a (only one shown). Each of the discharge valve 29a is formed from a sheet
of resilient material into a split tube having a longitudinal slit. The tubular discharge
valve 29a is spread against its own resliency when it is retained on the stopper projections
28a - 28e of the cover 25a, 25b. The discharge valve 29a thus attached has outer peripheral
portions normally held in contact with the bottom wall of the recess 24a to close
the open ends of the respective discharge holes 22a - 22c.
[0024] The high pressure chamber 18 and the valve-receiving chambers 27a are held in fluid
communication with each other by means of a pair of discharge connecting holes 30a,
30b extending through the cylinder 1 and the front side block 7a. The discharge connecting
holes 30a, 30b are disposed radially inwardly of the first O-ring 14a so that they
are held gas-tight by means of the O-ring 14a.
[0025] With this construction, when the drive shaft 4 is driven to rotate the rotor 2 in
one direction, the vanes 6a - 6e slide along the inner wall of the cylinder 1 to cause
the compression chambers 8a - 8e to successively increase and decrease in size with
each revolution of the rotor 2. As the compression chambers 8a - 8e increase in size
or volume, they are brought to fluid communication with the low pressure chamber 17
through the intake holes 21a, 21b, whereupon a gas which has been introduced from
the intake port 15 into the low pressure chamber 17 is drawn into the compression
chambers 8a - 8e through the intake holes 21a, 21b. Then the compression chambers
8a - 8e gradually decrease in size and when succeeding vanes 6a - 6e move past the
intake holes 21a, 21b, the gas is trapped in the compression chambers 8a - 8e. Thus,
the compression is commenced. A further movement of the rotor 2 causes the preceding
vanes 6a - 6e to move past the discharge holes 22a - 22c whereupon the compression
chambers 8a - 8e communicate with the discharge holes 22a - 22c and then the discharge
valves 29a are forced by the pressure in the compression chambers 8a - 8e to retract
away from the discharge holes 21a - 21c until the valves 29a engage the stopper projections
28a - 28c of the covers 25a, 25b. Consequently, the gas is discharged from the compression
chambers 8a - 8e through the discharge holes 22a - 22c into the valve-receiving chambers
27a. Then the gas flows through the discharge connecting holes 30 into the high pressure
chamber 18, and finally is discharged from the discharge port 16 to the outside of
the compressor.
[0026] A second embodiment shown in FIG. 5 differs from the foregoing embodiment in that
the compressor has an intake side at its front end and a discharge side at its rear
end. The compressor includes a front side block 7a which is replaceable with the rear
side block 7b of the foregoing embodiment. The front side block 7a includes a pair
of intake holes 21a (only one shown) while a non-illustrated rear block is provided
with discharge holes. A front head 11a of the compressor has an intake port 15 which
is corresponding to the discharge port 16 of the compressor of the foregoing embodiment.
Other structural details of the compressor are the same as those of the foregoing
embodiment with the exception that a low pressure guide groove 20 is formed in the
front head 11a instead of the drive shaft 4.
[0027] The like or corresponding parts are indicated by the same reference characters throughout
several views and due to the structural similarity, a further description is not necessary.
[0028] According to a third embodiment shown in FIGS. 6 through 9, a sliding-vane rotary
compressor includes a displacement-adjustment mechanism incorporated in a rear side
block 7b and a rear head 11b. The compressor of this embodiment is the same as the
compressor of the first-mentioned embodiment except the shape of the rear side block
7b and the internal construction of the rear side block 7b and the rear head 11b.
[0029] The displacement-adjustment mechanism is the same in principle as the mechanism as
shown in Japanese Utility Model Laid-open Publication No. 55-2000. The mechanism includes
a ring-shaped adjustment member 31 for adjusting the compression starting position.
The adjustment member 31 is rotatably fitted in an annular groove 32 formed in one
surface of the rear side block 7b facing the cylinder 1. The adjustment member 31
has a pair of diametrically opposite peripheral cut-out recesses 33a, 33b normally
held in communication with a pair of intake holes 21a, 21b, respectively, formed in
the rear side block 7b. With this arrangement, the circumferential position of the
cut-out recesses 33a, 33b varies as the adjustment member 31 is turned so that it
is possible to adjust the compression starting position, i.e. the position in which
the vanes 6a - 6e begins to block fluid communication between compression chambers
8a - 8e and the intake holes 21a, 21b.
[0030] A torsion coil spring 34 constituting a resilient biasing or urging means is resiliently
disposed and acting between the rear side block 7b and the adjustment member 31 for
urging the latter to turn in the clockwise direction in FIGS. 7 and 8. The adjustment
member 31 includes a pair of tongue-like pressure-retaining portions 35a, 35b projecting
perpendicularly from the body of the adjustment member 31. The pressure-retaining
portions 35a, 35b are slidably received in a pair of guide grooves 36a, 36b, respectively,
formed in the rear side block 7b and extending contiguously from the intake holes
21a, 21b. Thus, there are two pressure chambers 37a, 37b defined between the guide
grooves 36a, 36b and the adjustment member 31. The pressure chambers 37a, 37b are
sealed from the outside by means of a seal member 38 which is fitted over the adjustment
member 31. The pressure chambers 37a, 37b communicate with each other via a pair of
connecting holes 38a, 38b extending through the rear side block 7b and also via a
connecting space 11b defined between the rear side block 7b and the rear head 11b.
One of the pressure chambers 37b is held in fluid communication with a valve-receiving
chamber 27a via an orifice 40 so that a metered flow of high pressure discharge gas
is introduced into the pressure chambers 37a, 37b. The other pressure chamber 37a
is connected with a low pressure chamber 17 through a connecting passage 41 formed
in the rear side block 7b.
[0031] The connecting passage 41 is opened and closed by a control valve 42 disposed in
the rear head 11b. The control valve 42 includes a bellows 43 capable of expanding
and contracting in response to the pressure in the low pressure chamber 17, a ball
valve element 44 connected to one end of the bellows 43, and a valve seat 45 against
which the valve element 44 is seated. The control valve 42 thus constructed operates
to vary the open area between the valve element 44 and the valve seat 45, thereby
adjusting the rate of communication between the low pressure chamber 17 and the pressure
chambers 37a, 37b.
[0032] The rear side block 7b has a radially extending low pressure connecting groove 46
through which the low pressure gas is introduced into a low pressure guide groove
20 in the drive shaft 4.
[0033] Operation of the displacement-adjustment mechanism is described in detail. When the
vehicle is cruising at low speed, the pressure in the low pressure chamber 17 is high.
Under such condition, the bellows 43 of the control valve 42 is kept contracted to
thereby move the valve element 44 in a direction to reduce the open area between the
valve element 44 and the valve seat 45. Consequently, the amount of high pressure
gas introduced through the orifice 40 into the pressure chambers 37a, 37b becomes
greater than the amount of gas escaping from the pressure chambers 37a, 37b through
the connecting passage 41 into the low pressure chamber 17. Thus the pressure in the
pressure chambers 37a, 37b is increased. With this pressure rise, the adjustment member
31 is caused to turn counterclockwise against the bias of the spring 34, thereby displacing
the compression starting position in the counterclockwise direction. As a result,
the compression starting timing is advanced, thereby increasing the amount of gas
to be trapped in the compression chambers 8a - 8e. The compressor is thus driven at
a large displacement.
[0034] When the vehicle is cruising at high speed, the pressure in the low pressure chamber
17 is low. Consequently, the bellows 43 of the control valve 42 is caused to expand
to thereby move the valve element 44 in a direction to increase the open area between
the valve element 44 and the valve seat 45. Under such condition, the amount of gas
escaping from the pressure chambers 37a, 37b is increased and the pressure in the
pressure chambers 37a, 37b is reduced. With this pressure drop, the adjustment member
31 is caused to turn clockwise under the force of the spring 34, thereby displacing
the compression starting position in the clockwise direction. As a result, the timing
when the cut-out recesses 33a, 33b are closed by the succeeding vanes 6a - 6e is retarded.
With this delaying, gas in the compression chambers 8a - 8e flows back into the low
pressure chamber 17, thereby reducing the amount of gas to be compressed in the compression
chambers 8a - 8e. The compressor is thus driven at a reduced displacement.
[0035] In the first and third embodiments, the like or corresponding parts are indicated
by the like or corresponding reference characters throughout several views.
[0036] Obviously, many modifications and variations of the present invention are possible
in the light of the above teaching. It is therefore to be understood that within the
scope of the appended claims, the invention may be practiced otherwise than as specifically
described.
1. A sliding-vane rotary compressor comprising:
(a) a cylinder and a rotor rotatably disposed in said cylinder so as to define therebetween
an operating compartment, said rotor carrying thereon a plurality of approximately
radially movable sliding vanes, there being defined between said cylinder, said rotor
and said vanes a plurality of compression chambers which vary in volume with each
revolution of said rotor;
(b) a pair of side blocks secured to opposite ends of said cylinder;
(c) a pair of heads secured to said side blocks, respectively, on opposite sides of
said cylinder;
(d) one of said side block and one of said heads secured to said one side block jointly
defining therebetween a low pressure chamber extending in fluid communication with
an intake port of said compressor;
(e) the other side block and the other head jointly defining therebetween a high pressure
chamber extending in fluid communication with a discharge port of said compressor;
(f) said one side block having an intake hole connecting said low pressue chamber
and said operating compartment;
(g) said cylinder having a recess defined in an outer surface thereof, and a discharge
hole having one end opening to said operating compartment and the other end opening
to said recess;
(h) a cover secured to said cylinder and extending over said recess to close the latter,
there being defined between said cylinder and said cover a valve receiving chamber;
(i) a discharge valve disposed in said valve receiving chamber for opening and closing
said discharge hole; and
(j) said cylinder and said other side block having a discharge connecting hole extending
between said recess and said high pressure chamber.
2. A sliding-vane rotary compressor according to claim 1, said discharge valve having
a tubular shape.
3. A sliding-vane rotary compressor according to claim 2, said tubular discharge valve
having a longitudinal slit.
4. A sliding-vane rotary compressor according to claim 1, said cover including a stopper
projection extending toward said cylinder and engageable with said discharge valve
to limit movement of the latter.
5. A sliding-vane rotary compressor comprising:
(a) a cylinder and a rotor rotatably disposed in said cylinder so as to define therebetween
an operating compartment, said rotor carrying thereon a plurality of approximately
radially movable sliding vanes, there being defined between said cylinder, said rotor
and said vanes a plurality of compression chambers which vary in volume with each
revolution of said rotor;
(b) a pair of side blocks secured to opposite ends of said cylinder;
(c) a pair of heads secured to said side blocks, respectively, on opposite sides of
said cylinder;
(d) one of said side block and one of said heads secured to said one side block jointly
defining therebetween a low pressure chamber extending in fluid communication with
an intake port of said compressor;
(e) the other side block and the other head jointly defining therebetween a high pressure
chamber extending in fluid communication with a discharge port of said compressor;
(f) said one side block having an intake hole connecting said low pressue chamber
and said operating compartment;
(g) said cylinder having a recess defined in an outer surface thereof, and a discharge
hole having one end opening to said operating compartment and the other end opening
to said recess;
(h) a cover secured to said cylinder and extending over said recess to close the latter,
there being defined between said cylinder and said cover a valve receiving chamber;
(i) a discharge valve disposed in said valve receiving chamber for opening and closing
said discharge hole;
(j) said cylinder and said other side block having a discharge connecting hole extending
between said recess and said high pressure chamber; and
(k) a displacement-adjustment mechamism incorporated in said one side block and said
one head for adjusting displacement of said compressor.
6. A sliding-vane rotary compressor according to claim 5, said displacement-adjustment
mechanism including:
(a) an adjustment member rotatably disposed in said one side block for adjusting a
compression starting position;
(b) resilient means for urging said adjustment member to turn in one direction;
(c) means defining a pressure chamber for producing a pressure acting on said adjustment
member to urge the latter to turn in the opposite direction against the force of said
resilient means, said pressure chamber being connected with said high pressure chamber
via an orifice; and
(d) a control valve for adjusting the rate of communication between said pressure
chamber and said low pressure chamber according to the pressure in said low pressure
chamber.